The past, present and future of tuberculosis diagnostics techniques

According to a recent World Health Organization report, tuberculosis (TB), an ancient disease with an enormous global impact, still ranks in the top ten causes of death worldwide. Pulmonary TB, where patients show symptoms like cough, fever, night sweat and weight-loss is highly contagious and poses serious public health concerns. If diagnosed in a timely manner nearly all patients infected with TB can be cured. However, TB remains one of the worldu0027s big healthcare-related challenges since treatment usually requires daily intake of multiple antibiotics for a prolonged period of six months. As such patient compliance, as well as tolerance to this multi-drug therapy, poses a big issue in many cases, resulting in relapse or development of drug-resistance. The increase in resistance to the different front-line TB drugs has led to the spread of multi-drug resistant tuberculosis (MDR-TB) and further prevents TB control. MDR-TB creates a higher burden on clinical management requiring prolonged treatment, and monitoring of adverse side-effects from alternate therapy. In addition, presence of co-morbidities (HIV, immunocompromised status, diabetes) can further complicate cure. Despite a lot of research, the diagnostic testing and the epidemiological investigation to control the spread of TB still require significant resources of clinical microbiology laboratories as well as public health services. This review article provides a brief overview of the past, present and future of the different diagnostic technologies used in tuberculosis. It covers the time-intensive culture-based technologies, along with the newer molecular technologies that have revolutionised TB diagnosis with faster turn-around-time. This review article also describes the technologies that rapidly determine the drug susceptibility or resistance of the bacterium, u0027Mycobacterium tuberculosisu0027, the causative agent of TB; and the technologies of molecular typing that help in an outbreak or prevent further spread of the disease. It discusses research that has contributed to further understanding of the biology of various strains in the u0027Mycobacterium tuberculosisu0027 complex, and their prevalence in humans globally and in New Zealand. Finally, the emerging technology of whole genome sequencing of u0027Mycobacterium tuberculosisu0027 and its possible applications in TB diagnosis is discussed.